Examples of semiconductor devices include power devices, such as switching elements. A power device is used, for example, in the form of a power conditioner of a photovoltaic power generation system, or is used to control the rotation of a motor. Module products each formed by housing a plurality of power devices in a block module are referred to as power modules.
For example, PATENT DOCUMENT 1 describes a conventional technique relating to power modules. FIG. 11 is a schematic cross-sectional view of a semiconductor device described in PATENT DOCUMENT 1.
As illustrated in FIG. 11, the semiconductor device according to PATENT DOCUMENT 1 includes a metal plate 103 containing copper (Cu) as the main ingredient, and an outer case 102 insert-molded together with a metal terminal 101. The metal plate 103 is fixed on a lower surface of the outer case 102 with an adhesive 104. An insulative substrate 105 having an interconnect pattern is joined onto the metal plate 103 with solder 106. A plurality of power semiconductor elements 107 including an insulated gate bipolar transistor (IGBT) and a freewheel diode are joined onto the insulative substrate 105 with solder (not shown). Electrodes (not shown) each formed on the surface of a corresponding one of the power semiconductor elements 107 and relay terminals 108 of the outer case 102 are connected together through an aluminum (Al) wire 109. A control substrate 112 is placed immediately above the power semiconductor elements 107. A control element 110 and passive components 111, such as a capacitor and a resistor, are mounted on the control substrate 112. The control element 110 controls the power semiconductor elements 107. The relay terminals 108 are inserted into the control substrate 112 to electrically connect the power semiconductor elements 107 to the control element 110. A region surrounding the power semiconductor elements 107 (the internal space of the outer case 102 between the metal plate 103 and the control substrate 112) is encapsulated with a resin material, such as a silicone gel 113, to protect the power semiconductor elements 107 from the external environment.
Furthermore, PATENT DOCUMENT 2 describes a configuration in which a bottom plate of a package extends beyond a package body toward an area surrounding the package body, and a portion of the bottom plate extending beyond the package body is secured onto a base by screws.